This invention relates generally to electromagnetic switchgear, and more particularly, to an electromagnet system for such switchgear, the electromagnet system having movable and stationary magnet portions wherein slots are provided at the pole surfaces for inserting metal parts which influence the magnetic flux.
German Pat. No. 1,270,655 describes an electromagnet system for electromagnetic switchgear wherein slots are provided at the pole surfaces of movable and stationary magnet portions for inserting metal parts which affect the magnetic flux. In the known system, a contactor has a plunger-type magnet system in a cup-shaped magnetic return yoke. A metal part which influences the magnetic flux, illustratively a short-circuit ring, is fastened at a plate which guides the lines of force and which rests against the cup-shaped magnetic return portion. This short-circuit ring causes a shift of the flux so that the switchgear is rendered usable for AC excitation.
A further known switching arrangement, particularly of the type having hinged-armature contactors is adapted for DC operation in accordance with German Petty Pat. No. 1,901,736. In this known system, a pole plate is bolted to the pole core which extends through the exciter coil of the angular magnet yoke. The pole plate increases the area of the pole core and cooperates with the hinged armature.